Edit: I rewrote my comment because I misunderstood yours. You could tie it to an "on-scroll" type of event, like how many text boxes will fire an event X milli

Edit: I rewrote my comment because I misunderstood yours. You could tie it to an "on-scroll" type of event, like how many text boxes will fire an event X milliseconds after a text edit event, so that they can process the text when the user is not likely to be typing. A single timer by itself won't busy-wait, but I agree that running a timer all the time is a waste. Just run it when scrolling, when CPU use will already be high.